That will do Jiri Lehecka's confidence a world of good as he outplays Novak Djokovic with a deep forehand followed by a neat volley at the net.

He wraps up the game as Djokovic goes agonisingly long, bringing oohs form the crowd when the ball landing is shown on the big screen.

Image source, Getty Images

What a match we've got going on over on John Cain Arena.

German second seed Alexander Zverev stormed his way through the opening set against Ugo Humbert in just 28 minutes, but there's been a huge momentum shift.

Humbert, the14th seed, has just wrapped up the second set and Zverev is looking slightly rattled.

The Frenchman has never reached the quarter-finals of a Grand Slam before.

Novak Djokovic opens with a double fault but his next serve is on point and Jiri Lehecka can't keep the ball in play.

Djokovic puts a backhand into the net but sees out the rest of the game, sealing it with an ace.

The umpire tells the players they have 20 seconds left to finish their warm-ups.

It's Serb seventh seed Novak Djokovic who will get us under way on Rod Laver Arena.

Jonathan Jurejko
BBC Sport in Melbourne

Image source, Getty Images

Earlier today, British number one Jack Draper ran out of steam as Carlos Alcaraz moved into the Australian Open quarter-finals.

Draper, seeded 15th, retired when he was trailing 7-5 6-1 against four-time major champion Alcaraz on a hot day in Melbourne.

The 23-year-old left-hander needed treatment off the court after the first set before abandoning the match at the end of the second.

He held both hands up to the crowd by way of an apology before going off Rod Laver Arena to a warm ovation.

"It is not the way which I want to win," said Alcaraz.

"I'm happy to play another quarter-final here in Australia, but I am sad for Jack – he doesn't deserve to be injured.

Full report.

Here comes Jiri Lehecka, sporting a pink t-shirt and white shorts.

Novak Djokovic, who's in a blue top and white shorts, greets Rod Laver Arena with a little wave and smile.

The players are about to do their warm-ups.

Image source, Getty Images

Novak Djokovic has created countless Australian Open moments over the years, but he's hoping to make one more in winning a record 25th Grand Slam.

Victory for the Serb seventh seed and 10-time winner in Melbourne would take him one clear of Margaret Court's all-time Slam record.

Standing in his way today is Czech 24th seed Jiri Lehecka, who is looking to reach the last eight in Melbourne for the second time.

The pair have only played each other once, with Djokovic winning last year's United Cup tie.

Image source, gett

Welcome back!

If you're just waking up, you can read up on Jack Draper's Australian Open exit here, where the Briton retired when he was trailing 7-5 6-1 against Spain's Carlos Alcaraz.

Now though, our attention turns to Novak Djokovic against Jiri Lehecka, with the pair bidding to join Alcaraz in the quarter-finals.

The pair are due to walk on court at Rod Laver Arena shortly.

BBC Radio 5 Sports Extra

We're going to take a quick break from live texting for now.

But don't worry! We'll be back for Novak Djokovic's match against Jiri Lehecka to get started on Rod Laver Arena at 08:00 GMT.

For now, though, you can keep up with all the action in Melbourne Park by tuning in to BBC Radio 5 Sports Extra at the top of this page.

Before his match against Carlos Alcaraz, Jack Draper had spent a whopping 12 hours and 34 minutes on court.

An extra hour and 35 minutes just proves too much for the British number one.

Remember, he arrived in Melbourne having played no build-up matches because of a hip injury so even making it to the fourth round was a pretty big deal.

Image source, Getty Images

More from Carlos Alcaraz on facing either Novak Djokovic or Jiri Lehecka: "I’m going to watch that one for sure. I have to recover now, as good as I can with my team. I’m going to take the time to watch it.

"That guy called Novak Djokovic, I played a few times against him Jiri Lehecka as well – it’s going to be really interesting match to watch and people are going to enjoy that much as much as I do."

On wearing shoes like Andre Agassi: "Last year I brought John McEnroe here, this year I’m bringing the Agassi shoes. Those players are legends from our sport .

"I can't say I looked up to him – I didn’t see them play – too young I guess but I know everything they did for the sport.

"It’s amazing to have the chance to be around them and be able to talk with them. It’s great to have them around."

Here's what Carlos Alcaraz had to say in his on-court interview: "It’s not the way I want to win the match to get through to the next round. I’m just happy to play in another quarter-final in Australia but a little bit sad for Jack, he’s a nice person. He doesn’t deserve to get injured.

"He couldn’t prepare the start of the season well because of an injury as well. I’m a little sad but I’m sure he’s going to come back stronger and I want to wish him a speedy recovery."

On his progress through the tournament: "I am just happy with the level that I’m playing on the court. Off the court I’m feeling really comfortable here in Australia. Physically I’m feeling great so coming into the second week of a Grand Slam it’s really important to feel well physically because right now the matches are even tougher, I’m just ready. I think I’m doing great things off the court.

"I’m excited about playing my second quarter-final in Australia and hopefully getting further this year."

Image source, Getty Images

Carlos Alcaraz is a class act, isn't he?

The Spaniard pays tribute to Jack Draper in his on-court interview before writing "You will be where you deserve. Get well soon Jack!" on the camera.

We'll bring you the full quotes from him in just a moment.

Image source, Getty Images

So, who has the daunting task of facing Carlos Alcaraz in the quarter-finals?

We'll find out soon. Novak Djokovic and Jiri Lehecka are up next on Rod Laver Arena to fight it out.

Image source, Getty Images

Annabel Croft
Former British number one on BBC Radio 5 Live and BBC Sounds

It’s such a shame because Draper has been so unlucky. We could see how much damage he can do and how uncomfortable he makes his opponents feel.

Jonathan Jurejko
BBC Sport in Melbourne

You felt this might be the moment for Draper to call it a day, but we weren't sure when he walked back to his chair.

After taking a moment to consider his options, Draper decides enough is enough.

He holds both hands up to the crowd as a way of an apology before going off to a warm ovation.

He is. Jack Draper calls for the trainer but after a quick chat, he shakes his head and the sweatbands come off.

The British number one trudges over to Carlos Alcaraz, who gives him a warm embrace.

Not the ending anyone wanted.

And all of a sudden, the second set is finished.

And Jack Draper could be too.

Gigi Salmon
BBC Sport tennis commentator on BBC Radio 5 Live and BBC Sounds

Draper is pulling up off shots. He’s digging into that hip area trying to ease or move something.

This really happened quite quickly.

Carlos Alcaraz gets it but he doesn't celebrate, instead holding a hand up to his opponent to try and make sure Jack Draper is OK.

A grimace on the face of the British number one tells you he is not.

Image source, Getty Images